An equipment system includes a battery unit (10) having a monitoring circuit (14), which detects at least one operating parameter of the battery unit (10) and furnishes a control signal, dependent on the operating parameter, for switching means (25, 31). The switching means control the charging and discharging process of the battery unit (10) and are located in the electrical device (20) and in the charger (30), respectively. From the battery unit (10), the control signal is transmitted to the switching means (25, 31) in the electrical device (20) and in the charger (30), respectively. By this provision of shifting the switching means (25, 31) out of the battery unit (10) into the electrical device (20) and into the charger (30), respectively, the heat development in the battery unit (10) and also its structure size are reduced.